Antigenuria in Gambian infants following immunization with a Haemophilus influenzae type b polyribosylribitol phosphate-tetanus toxoid protein conjugate (PRP-T) vaccine.

During a Haemophilus influenzae type b (Hib)-conjugate vaccine trial, the prevalence and duration of antigenuria after vaccination was studied in 102 Gambian infants aged 51 to 175 days. Urine samples were collected at 0, 1, 3, 7, 14, 21 and 28 days postvaccination and tested for Hib antigen by latex agglutination using Biomérieux and Directigen reagent kits. Biomérieux positive reactions were found in 6 of 247 (2.4%) samples from vaccinated children and in 8 of 199 (4.0%) from nonvaccinated children (chi 2 = 0.47; 1 df; p = 0.5). In contrast, Directigen positive reactions were obtained with 86/242 samples (35.5%) from vaccinated children and from 28/190 (14.7%) from non-vaccinated children (chi 2 = 22.7; 1 df; p < 0.0001). The highest rate of antigenuria was detected in samples collected on Day 7 after vaccination when 24 of 30 (80%) were positive. Antigenuria following vaccination was frequent and may complicate the use of this test as a means of diagnosing invasive Hib disease in vaccinated children.

Latex particle agglutination tests on the cerebrospinal fluid. A reappraisal.

Rapid diagnostic tests are often used to identify microbial etiology of infection early. Latex particle agglutination (LPA) tests on the cerebrospinal fluid (CSF) are frequently used for purpose of rapid diagnosis. We evaluated their usefulness in management of patients with suspected meningitis. We also evaluated the cost effectiveness of LPAs during an 11-month period; 1,540 CSF specimens were tested for H. influenzae type b, Group B streptococcal (GBS), N. meningitidis and S. pneumoniae using LPAs. Only 27 were positive. LPAs were useful in management of only the neonates with GBS infection. On the whole, LPAs were very expensive and not cost-effective.

Inappropriate antidiuretic hormone in children with viral meningitis.

Urinary excretion rates of antidiuretic hormone were determined by radioimmunoassay in children with bacterial (6) and viral (11) meningitis, and in children with other febrile illnesses (7). These values were compared to normal data obtained from 50 healthy, normally hydrated children ranging in age from 1 week to 9 years. Plasma sodium concentrations were measured in the sick children; urine osmolality and creatinine concentrations were measured in all children. Upon admission, all children with bacterial meningitis and 64% of those with viral meningitis had urinary antidiuretic hormone excretion rates greater than 2 S.D. above values obtained from age-matched controls. Fifty-seven percent of children with other febrile illnesses had similarly elevated antidiuretic hormone values; however, only in the bacterial and viral meningitis groups were antidiuretic hormone excretion rates inappropriate because they occurred when serum sodium concentrations were found to be normal or low normal (i.e., 136 +/- 2 mEq/L and 137 +/- 1 mEq/L, respectively). The average serum sodium in the group with other febrile illnesses was higher (146 +/- 5 mEq/L; p less than 0.05) and could represent an appropriate stimulus for antidiuretic hormone release. In spite of high levels of antidiuretic hormone, most viral meningitis patients did not concentrate their urine, probably because all except 2 were younger than 2 months of age. We conclude that viral meningitis, like bacterial meningitis, frequently is associated with inappropriate antidiuretic hormone secretion; however, most children with viral meningitis may be protected from developing hyponatremia because of their inability to concentrate their urine.

Counterimmunoelectrophoresis in the diagnosis of acute infection.

Clinical experience with counterimmunoelectrophoresis (CIE) in a large university teaching center was reviewed for 1,042 specimens from 667 patients over a 2,5-year period. Urine was the fluid tested most frequently, and infants six to 12 months of age were most frequently positive. For analysis, diagnostic categories were separated into meningitis and nonmeningitis infections. CIE identified 69% of the patients with meningitis, with an early diagnostic with an early diagnostic value over the Gram stain of 25% but with a residual diagnostic-value postculture report in only 9% of these patients. In patients with nonmeningitis infections, however, the early diagnostic value was 49% overall and 74% for pneumonia, with a residual diagnostic-value postculture report of 25% overall and 47% for pneumonia. Cross-reactions were observed in two patients. Thus, CIE appears to be most useful as an ancillary diagnostic test in culture-negative patients.

Latex agglutination in diagnosis of bacterial infections, with special reference to patients with meningitis and septicemia.

Antibody-sensitized latex particles were used to demonstrate specific bacterial antigens in cerebrospinal fluid, blood and urine. Difficulties with reported nonspecific agglutinations appear to have been overcome. The method seems to be sensitive, specific, and simple to perform, and shows a better detection rate than culture or countercurrent immunoelectrophoresis. Urinary excretion of Haemophilus influenzae antigens was followed. The diagnostic usefulness of demonstrating such antigens at a later stage of disease is discussed.